fix(eslint-plugin): [no-shadow] fix static class method generics shad…

…owing class generics (#3393) Fixes #2592 Unfortunately I think this is impossible to solve from the scope analysis side.. So I opted instead to just ignore it from the lint rule.
typescript-eslint · May 15, 2021 · b1e1c8a · b1e1c8a
1 parent b85261c
commit b1e1c8a
Show file tree

Hide file tree

Showing 2 changed files with 98 additions and 0 deletions.
diff --git a/packages/eslint-plugin/src/rules/no-shadow.ts b/packages/eslint-plugin/src/rules/no-shadow.ts
@@ -126,6 +126,84 @@ export default util.createRule<Options, MessageIds>({
       return util.isFunctionType(id.parent);
     }
 
+    function isGenericOfStaticMethod(
+      variable: TSESLint.Scope.Variable,
+    ): boolean {
+      if (!('isTypeVariable' in variable)) {
+        // this shouldn't happen...
+        return false;
+      }
+
+      if (!variable.isTypeVariable) {
+        return false;
+      }
+
+      if (variable.identifiers.length === 0) {
+        return false;
+      }
+
+      const typeParameter = variable.identifiers[0].parent;
+      if (typeParameter?.type !== AST_NODE_TYPES.TSTypeParameter) {
+        return false;
+      }
+      const typeParameterDecl = typeParameter.parent;
+      if (
+        typeParameterDecl?.type !== AST_NODE_TYPES.TSTypeParameterDeclaration
+      ) {
+        return false;
+      }
+      const functionExpr = typeParameterDecl.parent;
+      if (
+        !functionExpr ||
+        (functionExpr.type !== AST_NODE_TYPES.FunctionExpression &&
+          functionExpr.type !== AST_NODE_TYPES.TSEmptyBodyFunctionExpression)
+      ) {
+        return false;
+      }
+      const methodDefinition = functionExpr.parent;
+      if (methodDefinition?.type !== AST_NODE_TYPES.MethodDefinition) {
+        return false;
+      }
+      return methodDefinition.static;
+    }
+
+    function isGenericOfClassDecl(variable: TSESLint.Scope.Variable): boolean {
+      if (!('isTypeVariable' in variable)) {
+        // this shouldn't happen...
+        return false;
+      }
+
+      if (!variable.isTypeVariable) {
+        return false;
+      }
+
+      if (variable.identifiers.length === 0) {
+        return false;
+      }
+
+      const typeParameter = variable.identifiers[0].parent;
+      if (typeParameter?.type !== AST_NODE_TYPES.TSTypeParameter) {
+        return false;
+      }
+      const typeParameterDecl = typeParameter.parent;
+      if (
+        typeParameterDecl?.type !== AST_NODE_TYPES.TSTypeParameterDeclaration
+      ) {
+        return false;
+      }
+      const classDecl = typeParameterDecl.parent;
+      return classDecl?.type === AST_NODE_TYPES.ClassDeclaration;
+    }
+
+    function isGenericOfAStaticMethodShadow(
+      variable: TSESLint.Scope.Variable,
+      shadowed: TSESLint.Scope.Variable,
+    ): boolean {
+      return (
+        isGenericOfStaticMethod(variable) && isGenericOfClassDecl(shadowed)
+      );
+    }
+
     /**
      * Check if variable name is allowed.
      * @param variable The variable to check.
@@ -321,6 +399,13 @@ export default util.createRule<Options, MessageIds>({
           continue;
         }
 
+        // ignore static class method generic shadowing class generic
+        // this is impossible for the scope analyser to understand
+        // so we have to handle this manually in this rule
+        if (isGenericOfAStaticMethodShadow(variable, shadowed)) {
+          continue;
+        }
+
         const isESLintGlobal = 'writeable' in shadowed;
         if (
           (shadowed.identifiers.length > 0 ||

diff --git a/packages/eslint-plugin/tests/rules/no-shadow.test.ts b/packages/eslint-plugin/tests/rules/no-shadow.test.ts
@@ -159,6 +159,19 @@ type Fn = (Foo: string) => typeof Foo;
       `,
       options: [{ ignoreFunctionTypeParameterNameValueShadow: false }],
     },
+    `
+export class Wrapper<Wrapped> {
+  private constructor(private readonly wrapped: Wrapped) {}
+
+  unwrap(): Wrapped {
+    return this.wrapped;
+  }
+
+  static create<Wrapped>(wrapped: Wrapped) {
+    return new Wrapper<Wrapped>(wrapped);
+  }
+}
+    `,
   ],
   invalid: [
     {